The goal of the project is to identify and characterize genes that are involved in the neural development of Drosophila. A genetic modifier screen for genes that interact with the organ-type selector gene cut was carried out, resulting in the identification of at least thirteen genes that appear to play a role in neurogenesis. Four of these are previously characterized genes and the remainder are uncharacterized lethal P-element insertion mutants. A majority of these mutant genes exhibit some type of neuronal defect when stained with neural-specific antibodies. This proposal aims to focus on three of the most promising genes identified in the screen. The mutant phenotype of these genes will be further characterized using a battery of cell-type specific antibodies. The genes will then be cloned using the plasmid rescue technique to recover a fragment of the corresponding genomic DNA. From that point, standard library screening and sequencing techniques will be used to complete the cloning project. The expression patterns of the genes will then be analyzed by in situ hybridization. The overexpression phenotype will be characterized using the UAS-GAL4 system. These gene will also be tested in genetic epistasis experiments with other known neural development genes to ascertain the precise positions that these genes occupy within the genetic hierarchy leading to neural development.